Data from: Variation in age and size in Fennoscandian three-spined sticklebacks (Gasterosteus aculeatus)

Average age and maximum life span of breeding adult three-spined sticklebacks (Gasterosteus aculeatus) were determined in eight Fennoscandian localities with the aid of skeletochronology. The average age varied from 1.8 to 3.6 years, and maximum life span from three to six years depending on the locality. On average, fish from marine populations were significantly older than those from freshwater populations, but variation within habitat types was large. We also found significant differences in mean body size among different habitat types and populations, but only the population differences remained significant after accounting for variation due to age effects. These results show that generation length and longevity in three-spined sticklebacks can vary significantly from one locality to another, and that population differences in mean body size cannot be explained as a simple consequence of differences in population age structure. We also describe a nanistic population from northern Finland exhibiting long life spans and small body size.本研究通过骨龄学（skeletochronology）方法，对芬诺斯坎迪亚（Fennoscandian）区域内8个采样位点的繁殖期成年三棘刺鱼（Gasterosteus aculeatus）的平均年龄与最大寿命进行了测定。研究结果显示，种群的平均年龄介于1.8至3.6年之间，最大寿命范围为3至6年，具体数值随采样位点的不同而存在差异。整体而言，海洋种群刺鱼的平均年龄显著高于淡水种群，但同一生境类型内部的年龄变异幅度仍较大。本研究同时发现，不同生境类型与种群间的平均体长存在显著差异；但在校正年龄效应带来的变异后，仅种群间的体长差异仍保持统计学显著性。上述结果表明，三棘刺鱼的世代长度与寿命在不同采样位点间存在显著差异，且种群平均体长的差异无法通过种群年龄结构的差异进行简单解释。此外，本次研究还记录了芬兰北部的一个矮小型种群（nanistic population），该种群兼具寿命较长与个体体型偏小的特征。